The Punjab National Bank unearthed a Rs 11,400-crore fraud at its branch in Mumbai.Reuters

Punjab National Bank has said that the amount of fraudulent transactions in the Nirav Modi case could be Rs 1,300 crore more than the current estimate of about Rs 11,400 crore.

"We have to inform that quantum of reported unauthorized transactions can increase by $204.25 million (approximately)," the bank said in a regulatory filing on Monday.

The state-owned lender, earlier this month, "detected some fraudulent and unauthorized transactions" at its Brady House branch in Mumbai.

Indian-born diamond jewellery designer Nirav Modi is at the centre of the Punjab National Bank scam and three other big jewellers - Gitanjali Gems, Ginni and Nakshatra - are also under the scanner of various investigative agencies.

The fraud revelation that started from Rs 280 crore has now reached over Rs 12,700 crore, about 10 times than the PNB's annual net profit of Rs 1,324 crore during 2016-17.

India's Enforcement Directorate (ED) has seized Nirav Modi's cars in the Rs 11,400-crore financial fraud at the Punjab National Bank.

The total seizure in the case now stands at Rs 5,826 crore, according to ED officials.

The Income Tax department attached property worth Rs 1,200 crore of the Gitanjali Group located in the Special Economic Zone in Hyderabad, newswire PTI reported.

Following the PNB scam, the external affairs ministry had suspended the passports of Nirav Modi and Gitanjali promoter Mehul Choksi for four weeks.